I don't do sneering or snobbery and I firmly believe everybody should read whatever they want to read free of condescension from anybody else.
However I will try to answer the question posed by CaptainOatFlosser as best I can.
Margaret Atwood is an important novelist because of the themes she tackles and people in the literary world deem her significant enough to make her the (equal) most short-listed person for the Booker Prize, widely regarded as the world's pre-eminent literary award. She is one of only 5 people to have won it twice. She has won other awards too numerous to mention.
Unlike some Booker Prize winners, her books also often top the best-sellers charts, so she has popular appeal too. Genre-wise she has written poetry, children's books, non-fiction and even graphic novels, so if there is a 'line', no matter how squiggly, Atwood is surely on the side of being a recognisable name.
Personally I would expect anyone working in a book environment, whether a paid library assistant or an unpaid volunteer who has chosen to work in a library, to be aware of her. I wouldn't be shocked into pearl-clutching about it, but I would be mildly surprised.